Aircraft generally comprise one or more onboard communication networks designed to allow communications between onboard devices, particularly onboard computers. In order to satisfy the regulatory requirements in regard to aircraft certification, an onboard communication network must be deterministic, that is to say that it must allow transmission of information from a sender device that is a subscriber to this communication network to one or more receiver devices that are subscribers to this communication network, with a duration of transmission of less than a predetermined duration as well as a guarantee of no information loss through the network. The ARINC 664 part 7 standard defines a deterministic onboard avionics communication network, based on a full-duplex switched Ethernet technology. Such a network may for example correspond to an AFDX® communication network. In a network in accordance with the ARINC 664 part 7 standard, each device is linked to a switch of the network and the communications between the various devices follow virtual links predefined during network definition and configuration. A virtual link is defined between a sender device and one or more receiver devices, via one or more switches of the network. Each virtual link follows a determined path in the network. A bandwidth is allocated to each virtual link and the routing of the various virtual links of the network is carried out in such a way that the sum of the bandwidths allocated to the virtual links following one and the same physical connection does not exceed the bandwidth supported by the physical connection. This is necessary in order to guarantee the determinism of the network. When a sender device that is a subscriber to the communication network wishes to send information to one or more receiver devices, it transmits this information in data frames on a virtual link of which this (or these) receiver device(s) is a recipient (are recipients). The dispatching of the data frames by the sender device is carried out while complying with constraints of temporal shaping (known as “traffic shaping”) of each virtual link. For a given virtual link, these constraints correspond in particular to a time interval between two successive dispatches of data packets on the virtual link, these data packets corresponding to sets of data frames. This time interval is usually known as a BAG (“Bandwidth Allocation Gap”). A BAG is defined for each virtual link during the design of the communication network. When a virtual link passes through a switch, this switch receives, on a first physical connection, data frames corresponding to this virtual link and it retransmits these data frames on a second physical connection. The retransmission, on the second physical connection, of the data frames corresponding to the various virtual links sharing this second physical connection is carried out in an asynchronous manner, as a function of the reception of the various data frames by the switch. For a given virtual link, this results in a phenomenon of “Jitter” corresponding to a temporal offset, with respect to the BAG defined for this virtual link, between successive dispatches of data packets on this virtual link by the switch. Each switch through which the virtual link passes has the effect of increasing the Jitter phenomenon, the temporal offsets due to the various switches passed through possibly being aggregated. During the reception of the virtual link by a receiver subscriber, this receiver subscriber implements a function (known as “traffic policing”) which carries out in particular a temporal check of the data packets received on the virtual link. This function checks in particular that the Jitter is less than a maximum value of Jitter permitted for the virtual link. Indeed, the network being a deterministic network, the value of the Jitter must always be less than this permitted maximum value of Jitter. During a step of demonstrating the determinism of the communication network, it is necessary to evaluate a maximum value of Jitter during the reception of each virtual link by a receiver subscriber, so as to check whether this maximum Jitter value is much less than the maximum value of Jitter permitted for this virtual link. The higher the number of virtual links and the higher the number of switches passed through by virtual links, the more complex is this demonstration. This demonstration provides furthermore for the computation, for each virtual link, of a transmission time on the virtual link between the sender subscriber and each receiver subscriber. This computation is complex having regard to the Jitter caused by passing through the various switches.
All the communications between devices are defined in advance, by defining the virtual links, so as to allow configuration of the switches: each switch comprises a configuration table dependent on the virtual links passing via this switch. The configuration of each switch is downloaded to the latter before its use. A switch generally comprises a significant number of communication ports, for example 24 ports for certain switches. Provision is also made for a redundancy of the switches so as to prevent a fault with a switch from giving rise to unavailability of the communications between certain devices: the communication network is duplicated on two sets of switches whose switches are interlinked in a similar manner. Each subscriber of the communication network is hooked up on the one hand to a switch of a first of the two sets of switches and on the other hand to the corresponding switch of the other set of switches. A modern aircraft can thus comprise a high number of switches, for example 14 switches on certain aircraft. This results in a weight, bulkiness and electrical consumption that it would be beneficial to reduce in order to improve the performance of the aircraft.